Hot Spots
Intraplate vulcanism
A hot spot is an area of persistent volcanic activity. Hot spots originate at unusually hot
areas of the mantle-core boundary. Overlying mantle melts forming plumes of magma
that rise and penetrate the crust forming volcanoes.
Hawaii, Iceland, and Yellowstone are examples of hot spots. Hot spots are generally
characterized by large outpourings of basaltic lava for relatively long periods of time.
Hot Spots active in the last 10 million years (from Abbott, 1996.) The 11 hot spots
beneath Antarctica are not shown.
The trace of a hot spot appears as a chain, such as an island chain. As the overlying
plate moves one volcano off the hot spot, another is formed. The Hawaiian Island Chain
is an example. The island of Hawaii has been formed in the last 1 million years. The
other Hawaiian islands to the Northwest are progressively older. Kauai was over the
hotspot approximately 5 million years ago. A new Hawaiian Island is being formed off
the southeastern coast of Hawaii.
The hot spot that is currently under the island of Hawaii has created a chain of islands
and seamounts that extend from Hawaii to the Aleutian trench (from Tarbuck and
Lutgens,1987.)
Hot Spots record changes in plate motions because they are believed to be relatively
stationary. These spots do not move and thus remain in fixed locations for tens of
millions of years. The Hawaiian Island-Emperor Seamount chain bend that occurred
about 40 million years ago. This is when the motion of the Pacific plate changed from
nearly due north to northwesterly.